Adjustable mercury dispensing apparatus



DeC- 12 1967 D. N. BROOKS y l ADJUSTABLE MERCURY DISPENSING APPARATUSFiled NOV. 18. 1965 DAVID N. BROOKS INVENTOR.

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United States Patent O 3,357,600 ADJUSTABLE MERCURY DISPENSING APPARATUSDavid N. Brooks, West Peabody, Mass., assignor to Sylvania ElectricProducts Inc., a corporation of Delaware Filed Nov. 18, 1965, Ser. No.508,459 Claims. (Cl. 222-217) ABSTRACT OF THE DISCLOSURE The inventiondescribes a dispenser for mercury, the dispenser having a slide with anopening therein; the opening being normally open to a mercury reservoirat one end and closed at the other by a slidable pin, the position ofthe maximum displacement of the pin being adjustable by a micrometer toregulate the volume of the opening, the slide moving the opening fromthe reservoir to a discharge outlet as the pin pushes the mercury out ofthe opening.

This invention relates to mercury dispensing apparatus useful in themanufacture of high pressure electric discharge devices containingmercury and particularly to apparatus for dispensing precise easilyvariable amounts of mercury.

In the manufacture of high pressure electric discharge devices, mercurydispensing apparatus is employed to introduce a given quantity ofmercury into the -arc tube. Older discharge devices did not requirecritical amounts of mercury and the equipment to dispense mercury intothe device similarly did not require precision. In present types of highpressure discharge devices, however, the q-uantity of mercury introducedtherein is extremely critical to achieve the desired light emission andcolor spectrum. Dispensing apparatus must therefore provide such-critical doses; moreover, the doses should be easily variable to permituse of the apparatus in the manufacture of various types of dischargedevices.

Conventional dispensing apparatus usually employs a slidable memberhaving a cavity of specified size therein, and which is movable betweena mercury reservoir and a discharge orilice. The cavity in the slidablemember iills with mercury from the reservoir and then releases thisamount of mercury into the discharge orifice when the member is moved tothe discharge position. Unless used in a vacuum, the cavity in suchconventional apparatus does not always lill completely thereby causingerror in the amount of mercury which is dispensed. Furthermore,dispensed amounts can be varied only by replacing the slidable memberwith another containing a different cavity size. Such interchanging ofparts is most inconvenient and does not lend itself to automatedequipment.

`In accordance with the present invention, the dispensing apparatuscomprises a vertically slidable member with a horizontal cylindricalbore therein and a metering pin adjustably disposed in the bore. Whenthe slidable member is in the raised position, mercury flows from areservoir into the cylindrical bore in an amount precisely determined bythe adjustment of the metering pin. As the member is lowered, themetering pin is cammed or Otherwise urged further into the bore causingthe mercury to be discharged into a suitable orifice and thence to theelectric discharge device being lled.

The invention will be more fully understood from the following detaileddescription, taken in conjunction with the accompanying drawing, inwhich:

FIG. 1 is a sectional elevation view of apparatus according to theinvention; and

FIG. 2 is a top view of the apparatus of FIG. l.

Referring to the drawing, there is shown an annular ice housing 10having a partially cylindrical member 12 disposed therein, and avertically slidable rectangular member 14 located in a slot 16 providedin member 12. A cylindrical hole 18 in member 12 provides the mercuryreservoir and has an opening 20 in the lower end of the reservoir forsupplying Imercury to the dispensing slide, as will be further explainedhereinafter. The lower portion of member 12 is semi-cylindrical and hasa groove 22 cut in this lower portion which communicates with adischarge oriice 24 in the bottom portion of housing 10. Member 14 has ahorizontal bore 26 formed in the lower end thereof, for example, in abushing 60 set in the lower end thereof as shown in FIG. 1, with ametering pin 28 slidably mounted in bore Z6 and having a magnetic head30 attached to the end of pin 28 outside the bore. Member 14 is slidablyretained in slot 16 by a rectangular element 32 held in position bysuitable fasteners such as set screws 34 and 35 threaded into holesprovided in the Wall of housing 10.

A micrometer mechanism 38 is attached to housing 10 with the micrometerspindle 40 being attached to a stop plate 42 containing a magnet 44 toprovide adjustment of the stop plate. Vertical movement of slide 14 isprovided by a solenoid 46 supported above housing 10 by an annularstructure 56 and cooperating with a magnetizable head 48 connected tothe slide via a rod 50. A damping Vane 52 is also connected to head 48via a rod 54.

In operation, the size of the bore is adjusted by varying the positionof pin 28 in the bore by means of micrometer 38, and discharge orifice24 is connected to an electric discharge device to be filled. Solenoid46 is energized from a suitable electrical source (not shown) to urgehead 48, and hence slide 14, to the raised position with bore 26 inalignment with opening 20, causing mercury to flow from the reservoirinto the bore in van amount determined by the position of pin 28.Solenoid 46 is now de-energized, allowing slide 14 to fall by gravity.When bore 26 reaches slot 22, head 30 is engaged by a camming block S8in the bottom of housing 10 which urges pin 28 into the bore causing themeasured amount of mercury therein to flow into orifice 24 and thence tothe device being fabricated. Although not always necessary, it has beenfound desirable to retard the rate of descent of slide 14, for example,via the damping action of Vane 452 in the mercury bath. In this way, themercury is dispensed at a slower rate, minimizing the tendency of-mercury to splatter into droplets. The solenoid is again energized toraise slide 14, and the hydrostatic force of the mercury, together withthe magnetic attraction of head 30 by magnet 44, moves pin 28 out ofbore 26 to a position determined by the adjustment of stop plate 42.Bore 26 Iills with the measured amount of mercury which is thendispensed in the manner described hereinbefore. It should be noted thatthe space within the bore, when conveying mercury, is completely filledby the mercury and the pin, since the pin pushes the mercury out; thuslittle air remains therein to interfere with complete filling of thebore by the mercury.

Apparatus according to the invention has been constructed of stainlesssteel and has been successfully operated to dispense mercury in precisequantities up to approximately milligrams. Various modifications andconstructional variations will occur to those versed in the art, and itis not intended to limit the true scope of the invention by what hasbeen particularly shown and described, except as indicated in theappended claims.

I claim:

1. Mercury dispensing apparatus comprising, a mercury containingreservoir, a discharge orifice, a slidable member containing an openingtherein and -a slidable pin adjustably disposed in said opening at oneend to close the same and tix the amount of mercury which can be held inthe opening, means for adjusting the position of said pin in saidopening at a iirst position of said slidable member, and means formoving said slidable member between said first position to allow mercuryin said reservoir to enter said opening and a second position to causesaid pin to move into said opening to push the mercury therein into saiddischarge orice.

2. Mercury dispensing apparatus comprising, a mercury containingreservoir, a discharge orifice, a slidable member containing an openingtherein and a slidable pin adjustably disposed in said opening at oneend to close the same and x the amount of mercury which can be held inthe opening, means for adjusting the position of said pin in saidopening at a irst position of said slidable member, means for movingsaid slidable member between said rst position and a second position,means operative when said slidable member is in its iirst position toallow mercury to iiow from said reservoir into said opening, and meansoperative when said slidable member moves t0 its second position to urgesaid pin into said opening to thereby push the mercury therein into saiddischarge orice,

3. Apparatus according to claim 2 in which said last mentioned meansincludes a camming surface to urge said pin into said opening.

4. Apparatus according to claim 2 in which said second mentioned meansincludes a solenoid operatively associated with a magnetizable core.

5. Apparatus according to claim 2 in which said rst mentioned meansincludes a micrometer screw.

References Cited UNITED STATES PATENTS 795,676 7/1905 Amrnen 222--361 X2,580,256 12/ 1951 Tacchella 222--309 X 2,854,170 9/1958 Borgardt et al.222-252 X 3,134,508 5/1964 Bayer et al 222--309 X ROBERT B. REEVES,Primary Examiner.

1. MERCURY DISPENSING APPARATUS COMPRISING, A MERCURY CONTAININGRESERVOIR, A DISCHARGE ORIFICE, A SLIDABLE MEMBER CONTAINING AN OPENINGTHEREIN AND A SLIDABLE PIN ADJUSTABLY DISPOSED IN SAID OPENING AT ONEEND TO CLOSE THE SAME AND FIX THE AMOUNT OF MERCURY WHICH CAN BE HELD INTHE OPENING, MEANS FOR ADJUSTING THE POSITION OF SAID PIN SAID OPENINGAT A FIRST POSITION OF SAID SLIDABLE MEMBER, AND MEANS FOR MOVING SAIDSLIDABLE MEMBER BETWEEN SAID FIRST POSITION TO ALLOW MERCURY IN SAIDRESERVOIR TO ENTER SAID OPENING AND A SECOND POSITION TO CAUSE SAID PINTO MOVE INTO SAID OPENING TO PUSH THE MERCURY THEREIN INTO SAIDDISCHARGE ORIFICE.